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The Sky This Month - October 2007

Milky Way (North)

We have all enjoyed the long months of summer, especially the awe inspiring views of the Milky Way Galaxy. This mystical glow of millions of distant suns now stands directly overhead as the sky darkens and sets before the break of dawn. This is also your last chance to catch Scorpius, the planet Jupiter and Sagittarius in that order, located in south-west skies.

Over the course of the night, as various portions of our home galaxy set in the south and west, the northern section along Cassiopeia, Perseus and Auriga remains prominent and prime for observing. Since these constellations reside above the forty-five degrees north latitude mark, they are termed as circumpolar and thus never set as seen from Canada.

A favourite target in the north is the Double Cluster in Perseus. In a low power eyepiece, two distinct open clusters greet you. The combined light of both members equal that of a fourth magnitude star. Keep in mind this is stretched over a wide area. Their estimated distances are 7,100 and 7,400 light years (ly) from us. Viewing the Double Cluster under very dark conditions is like seeing diamonds on black velvet.

Some one and three quarter degrees from the Alpha star is NGC281, the Pacman Nebula. This diffuse nebula has a reddish glow is telling us it has active hydrogen molecules. NGC281 is fairly bright so it can be glimpsed in binoculars under superb dark conditions.

Although there are a large number of open clusters available in this section of sky, there are a few galaxies for your viewing pleasure. IC 10 is one such object. It is deemed as an outlying member of the Local Group of Galaxies. Lying 4.5 million ly, IC10 is 50% farther than the Andromeda Galaxy but glows at only magnitude 10.2. This galaxy possesses a large number of star forming regions.

Moving to the eastern part of Cassiopeia’s boundary is a trio of objects. NGC 1027 is a rich open cluster measuring 2/3rd the moon’s width. With a magnitude of 6.7, it is a guide post to IC 1805 aka the Heart Nebula on the right and Soul Nebula on the left. Both are being lit by young and hot blue stars. The Heart and Soul Nebulas lie about 6,000 ly from us.

One of the best examples of an edge on galaxy is NGC 891. With the plane of this galaxy lined up with our planet, NGC 891 takes on a pencil shaped appearance and exhibits the classic dust lane structure running along the outer perimeter.

NGC 1514 in Perseus is a difficult 10th magnitude planetary nebula. Astronomers believe there might be two stars in this planetary nebula orbiting each other between four to nine days. NGC 1514 measures less than 2 arc minutes across.

Keep moving from Cassiopeia through Perseus and you will land on Auriga. No less than three Messier objects take up residence here, namely M36, 37 and 38. Of the three I really like M37 with its even splash of stars.

Mars is now placed at the highest part of the ecliptic with the Mighty Hunter – Orion just below it. With each passing day our two worlds are moving closer until December 18th. At that point the red planet will be 88 million km. Mars will become stationary on November 15 and begin its retrograde motion against the normal flow of the stars. It is now unmistakably bright being a yellowish-orange colour.

A nice planetary grouping along with the waning crescent Moon will take place on Sunday morning before sunrise. The Moon will be nestled between Venus on the right and Saturn on the left. The brightest star of Leo finishes the portrait at the one o’clock position.

Autumn is prime time to catch the Zodiacal Lights. This triangular column is light is seen in the fall in eastern skies before sunrise and springtime in the west after sunset. With theSun lying very close to the celestial equator, the dust of the solar system is illuminated thus allowing us to view this debris along our solar system’s plane. This is comparable to looking at a dusty table edge on. Commencing October 10th with the absence of the morning Moon, you will have a two week period to catch and photograph this phenomena.

October also plays host two a couple of meteor showers. The first is call the Draconids and it will peak on the October 9th at 4:30 UT. The rates of this particular show are unpredictable being from periodic to storm levels. The Draconids however occur 3 nights before the new Moon so no interference.

The second celestial show will be the Orionids. Although scheduled to peak on October 21st, its entire duration lasts from October 2 to November 7th. At its height, the hourly rate of 25 meteors might be seen as the waxing gibbous Moon will interfere.

Venus will slide about 3 degrees south of the ringed planet Saturn before dawn breaks on the morning of the 15th and attains greatest western elongation (highest point above the eastern horizon at 46 degrees) on the 28th.